anyone know what could cause 10g link flapping between cisco 6807XL's

Got complaints from remote users that their SSH sessions were disconnecting mid jobs and I decided to investigate and noticed the 10g L3 link between our core switch (Te7/1) and our distribution switch (Te7/3) was flapping for a millisecond and OSPF adjacency between them as a result was flapping as well.

Both are cisco 6807XL, there is a tap between this link though.

looking at the logs on the link on the dist switch, it goes down and up for a millisecond.

Jan 3 08:47:42.661 pst: %LINEPROTO-5-UPDOWN: Line protocol on Interface TenGigabitEthernet7/3, changed state to down

Jan 3 08:47:43.797 pst: %LINEPROTO-5-UPDOWN: Line protocol on Interface TenGigabitEthernet7/3, changed state to up

Jan 3 08:52:45.627 pst: %LINEPROTO-5-UPDOWN: Line protocol on Interface TenGigabitEthernet7/3, changed state to down

Jan 3 08:52:46.703 pst: %LINEPROTO-5-UPDOWN: Line protocol on Interface TenGigabitEthernet7/3, changed state to up

Jan 3 09:04:58.480 pst: %LINEPROTO-5-UPDOWN: Line protocol on Interface TenGigabitEthernet7/3, changed state to down

Jan 3 09:04:59.588 pst: %LINEPROTO-5-UPDOWN: Line protocol on Interface TenGigabitEthernet7/3, changed state to up

but this millisecond is enough to bring down the OSPF adjancency between them, as shown in the logs from the core below...

Jan 3 08:47:45.805 pst: %OSPFv3-5-ADJCHG: Process 10343, Nbr 12.9.2.24 on TenGigabitEthernet7/1 from LOADING to FULL, Loading Done

Jan 3 08:47:48.409 pst: %OSPF-5-ADJCHG: Process 10343, Nbr 12.9.2.24 on TenGigabitEthernet7/1 from LOADING to FULL, Loading Done

Jan 3 08:52:46.707 pst: %OSPF-5-ADJCHG: Process 10343, Nbr 12.9.2.24 on TenGigabitEthernet7/1 from LOADING to FULL, Loading Done

Jan 3 08:52:48.791 pst: %OSPFv3-5-ADJCHG: Process 10343, Nbr 12.9.2.24 on TenGigabitEthernet7/1 from LOADING to FULL, Loading Done

Jan 3 09:04:59.592 pst: %OSPF-5-ADJCHG: Process 10343, Nbr 12.9.2.24 on TenGigabitEthernet7/1 from LOADING to FULL, Loading Done

Jan 3 09:05:01.592 pst: %OSPFv3-5-ADJCHG: Process 10343, Nbr 12.9.2.24 on TenGigabitEthernet7/1 from LOADING to FULL, Loading Done

I'm trying to figure out why it's flapping. I have checked the physical links and did a "sh int te7/1 transceiver" to see the optical Tx/Rx power and they are within normal range.

on the dist switch(Te7/3):

Temp (celsius) 34.8

Volt (v) N/A

Current (mA) 35.5

Optical Tx Power (dBm) -0.2

Optical Rx Power (dBm)-5.5

on the core(te7/1):

Temp (celsius) 29.4

Volt (v) 3.29

Current (mA) 34.4

Optical Tx Power (dBm) -0.6

Optical Rx Power (dBm)-3.6

or could this be caused by the tap that is in the middle?

thanks